Panelboard with insulative snap-in support means

ABSTRACT

A panel assembly comprising a pair of bus bar structures and an insulating support structure that supports the bus bar structures in a particular relationship with adequate spacing and insulation between the bus bar structures which are of opposite polarity.

Unite States Patent [1 1 Coley Oct. 30, 1973 [75] Inventor: Kenneth R.Coley, Fairfield, Conn.

[73] Assignee: Westinghouse Electric Corporation,

Pittsburgh, Pa.

[22] Filed: Nov. 1, 1972 [211 App]. No.: 302,950

[52] 0.8. CI. 317/119, 174/71 B [51] Int. Cl. 02b l/20 [58] Field ofSearch 174/71 B, 728; 317/1 19, 120

[ 56] References Cited UNITED STATES PATENTS 3,371,251 2/1968 Speck317/119 2,457,002 12/1948 Spiro 174/50 Primary ExaminerRobert K.Schaefer Assistant Examiner-Gerald P. Tolin AttorneyA. T. Stratton etal.

ABSTRACT A panel assembly comprising a pair of bus bar structures and aninsulating support structure that supports the bus bar structures in aparticular relationship with adequate spacing and, insulation betweenthe Bus bar structures which are of opposite polarity.

9 Claims, 9 Drawing Figures PAIENIEBflcfso ms EL K E a Q a E mi SHEET10F 5 Pmtmmnmamm 3,769,553

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SHEET 5 BF 5 PANELBOARD WITH INSULATIVE SNAP-IN SUPPORT MEANS BACKGROUNDOF THE INVENTION 1. Field of the Invention This invention relatesgenerally to electric distribution systems and more particularly to anelectric panel assembly in which bus bars are attached to a rigidsupport member without the use of separate or external fasteners.

2. Description of the Prior Art 1 Generally, a panel assembly or loadcenter of the type shown in U.S. Pat. No. 3,349,292 issued to James F.Meacham on Oct. 24, 1967, serves asdistribution centers in mainelectrical circuit to many branch circuits. Panel assemblies areutilized in both' one-phase and three-phase insulations wherein bus barsof positive and negative potentials are mounted on a dielectric supportstructure. Some other panel assemblies of prior construction have thedisadvantage of including separate fastening means for fastening the'busbars in place of the support structure, whereby additional cost andinconvenience is required in assembling the panel assemblies. Y

SUMMARY OF THE INVENTION A panel assembly is provided comprising anelongated insulating support structure and a pair of elongated bus bars;Each of the bus bars comprises an elongated main body part and aplurality of stab parts extending from the main body part in a spacedrelationship spaced lengthwise relative to the main body part. Theinsulating support structure comprises a plurality of spaced ledge partsat each of two opposite sides thereof. At each of the opposite sides ofthe insulating support structure all adjacent spaced ledge parts arespaced by a stab-receiving slot. The spaced ledge parts and thestab-receiving slots of the two opposite sides are staggered lengthwisesuch that eachstab-receiving slot at each side of the insulating supportstructure is opposite a ledge part of the opposite side of theinsulating support structure. The pair of bus bars are supported on theopposite sides of the insulating support structure with the spaced stabparts of each bus bar being positioned in the associated slots and withthe spaced ledge parts of the associated side of the insulating supportstructure being positioned over parts of the main body part of theassociated bus bar. The stab parts of the pair of bus bars arepositioned in an interleaved relationship aligned lengthwise along theinsulating support structure. The insulating support structure comprisesa pillar portion beneath eachof the stabreceiving slots for increasedsupport. Each pillar position and the bus bars comprise cooperatinginterengaging snap-in 1 parts for retaining the bus bars in the mountedposition. The improved panel assembly is ex pandable to satisfy a numberof circuit capacity requirements from eight through 42 circuits with theinsulating support structure comprising a maximum of only two differentkinds of insulating support members in a manner to be hereinafterspecifically described.

The advantage of the panel assembly ofthis invention is that separatefastening devices for retaining the bus bars in place on the mountingstructure are unnecessary, because snap-in fastening means are moldedintegrally with the support structure. Moreover, the particularconfiguration of this support structure is such that it includesresilience even where it is composed of a thermal setting resinousmaterial such as a phenolic resin.

- BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a plan view of a panelassembly constructed in accordance with principles of the subjectinvention;

FIG 2 is a sectional view, taken generally along the line IIII of FIG.1;

FIG. 3 is an exploded view, with some parts shown in section, of theinsulating support structure and bus bars of FIG. 1;

FIG. 4 is a sectional view of the insulating support structure takengenerally along the line IVIV of FIG. 3 with the bus bars of FIG. 3shown as they are being moved into the mounted position with the ledgeparts of the mounted position with the ledge parts of the insulatingsupport member structure flexed upwardly to the position shown in FIG. 3wherein the ledge parts are resiliently charged to provide a snap-inengagement with the bus bars reach the fully mounted position of FIG. 1;

FIG. 5 is a bottom view taken on the line VV of FIG. 4;

FIG. 6 is a vertical sectional view taken on the line VI VI of FIG. 5;and

FIG. 7 is a view similar to FIG. 3 of a different bus bar structure anddifferent bus bars having a different circuit capacity from that seen inFIG. 3;

FIG. 8 is a plan view of the parts of FIG. 7 in the assembled position;and

FIG. 9 is a plan view illustrating another embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings,there is shown, in FIGS. 1 and 7, a panel assembly 5 comprising a sheetmetal supporting pan 7 that may be supported in a loadcenter orpanelboard enclosure in a well known manner. The supporting pan 7comprises a lower support part 9 and two upper supporting shelf parts11. Two retaining plate structures 13, each of which comprises aplurality of retaining books 15, are fixedly supported on the shelfparts 11 of the supporting pan 7. I

An insulating support structure 17 is secured to the support pan 7 bymeans of screws 19 that pass through suitable openings in the supportstructure 17 and that are threaded into the support pan. The supportstructure 17 is an elongated member molded as an integral unit of anelectrically insulating material. It comprises a main body support part21 extending the length of the structure 17 and a plurality of ledgeparts 23 extending outward at the front of the support structure 17 ateach of two opposite sides of the main body support part 21. A pluralityof transversely extending stab-receiving slots 27 (FIG. 3) are formed ateach of the two opposite sides of the support structure 17 such thatthere is a stab-receiving slot 27 between each of adjacent ledge parts23 at each side of the support structure 17. As can be seen in FIG. 3,the support 17 is constructed with the spaced ledge parts and thestab-receiving slots of the two opposite sides being staggeredlengthwise such that each stab-receiving slot at each side of theinsulating support structure 17 is opposite a ledge part 23 of theopposite side of the insulating support structure 17. t

The insulating support structure 17 is molded such that there is atransversely extending supporting pillar portion 29 extending from thesupporting main body portion 21 under each of the stab-receiving slots27. The back surfaces of the pillar portions 29 and the back surface ofthe main body portion 21 are flat surfaces that rest on the pan 7 tosupport the structure 17. A pair of slots 33 are formed at the oppositeends of the supporting structure 17 for a purpose to be hereinafterdescribed. As can be seen in FIG. 3, openings 35 are provided in themain body supporting part 21 for receiving the mounting screws 19 (FIG.1).

A pair of bus bars 39 and 41 are supported on the insulating supportstructure 17 and are composed of electriccally conducting material. Eachof the bus bars 39 and 41 (FIG. 3) comprises a flat elongated main bodyportion 43 and a plurality of flat stabs 45 that are bentover from themain body portion 43 to extend along planes generally normal to theplane of the main body portion 43 in the manner disclosed in FIGS. 2 and3. Each of the bus bars 39 and 4l'is formed with a plurality of spacedapertures 47 in the main body part 43 thereof.

1 In addition, the insulating support structure 17 is provided witha'plurality of projections 49. Each projection 49 is located at theother end portion ofthe pillar portion 29 where each projection isaligned with a corresponding opening 47 in the bus bars 39 and 41. Whenthe bus bars are assembled with the insulating support structure 17,each projection 49 snaps into place within its corresponding opening 47.The insulating support structure 17 is also provided with secondprojections 59 on the undersurface of the ledge parts 23 which cothesupport structure 17 and the projections 59. To fav cilitate insertionof the bus bars 39 .and 41 into their mounted positions within theinsulating support structure 17, each protrusion 65 is provided with abeveled surface 67 which confronts the leading edge of the bus bar 39 or41 as-it is inserted into place, thereby causing the ledge parts 23 toflex upwardly slightly during assembly until the several apertures 47come into alignment with the corresponding projections 59 and snao intoplace therein.

During the assembly of the panel assembly 5, the retaining structures 13(FIGS. 1 and 2) are fixedly secured to the supporting pan member 7. Theinsulating movement of the bus bars 39, 41', each of the stabs 45 movesinto the associated stab-receiving slot 27, and in the final positionsof the bus bars 39, 41 the stabs 45 are positioned in an interleavedrelationship aligned lengthwise along the center portion of theinsulating support structure 17 as seen in FIG. 1. The bus bars 39, 41rest on the flat front surfaces of the pillar portions 29. Theinsulating support structure 17, and the bus bars 39, 41 are shown inFIG. 4 in a position reached during the mounting operation of the busbars prior to the time when the bus bars reach the fully mountedposition. As the bus bars 39, 41 are moved into position sliding overthe front surfaces of the pillar portions 29, the ledge portions 23 flexupward as shown in FIG. 4 spring charging the resilient ledge portions.When the bus bars 39, 41 reach the fully mounted position seen in FIG.1, the spring charged ledge portions 23 snap downward with theprojection 59 moving into the openings 47 in the bus bars 39, 41 toprovide an interlocking engagement between the insulating supportstructure 17 and the bus bars 39, 41 to thereby retain the bus bars inthe mounted position without the need of screws or other types ofseparate fastening members.

When the panel assembly is mounted at-an installation a plurality ofcircuit breakers are mounted on the assembly and connected to theconducting stabs in a well known manner. The circuit breakers, two ofwhich are seen at 61 in FIGS. 1 and 2, may be of the type disclosed inthe patent to L. W. Dyer, U.S. Pat. No. 2,677,025, issued Apr. 27, I954,and assigned to the assignee of the instant-case. Each of the circuitbreakers 61 comprise an electrically insulating housing 63 having anopening handle 65 extending from the front of the housing, whichhandleis movable between two operating positions to open and close apair of contacts enclosed within the housing in a well known manner.Each of the circuit breakers is mounted at line end thereof on theassociated conduiting stab 45 by means of a plug-in or clip-on typeconnecting terminal structure that comprises a pair of resilientconducting termi-' receiving the associated hook member 15 to retaintheload-end of the circuit breaker in place.

During the mounting operation, the load end of the circuit breaker isfirst moved into position with the associated hook portion 15, andthereafter the circuit breaker is pivoted down into the fully mountedposition seen in FIGS. 1 and 2. Each of the circuit breakers 61 isprovided with a well known type of solderless terminal connector at theload end thereof to permit connection of the circuit breaker in anelectric circuit. Only two circuit breakers are disclosed in FIG. 1, itbeing understood that at an installation a separate pair of circuitbreakers 61 may be connected to each of the conducting stabs 45. Thus,each of the conducting stabs 45 electrically feeds two circuit breakersin the panel assembly. The bus bars 39, 41, when connected in anelectric circuit, are of opposite polarity, and it is necessarytoprovide adequate insulation and spacing between the bus bars inaccordance with electrical standards. It can be seen, with reference toFIG. 1, that each of the ledge parts 23, at each side of the insulatingsupport structure 17, is opposite a stab-receiving slot 27 of theopposite side of the insulating support structure 17 so that each of thestabs 45 is insulated from the main body portion of the opposite bus barwith the ledge part adjacent the stab 45 covering part of the main bodyportion of the opposite bus bar. The insulating support structure 17 andbus bars 39, 41 are so constructed and arranged that the bus bars, whichare of opposite polarity, are adequately spaced and insulated from eachother.

The panel assembly illustrated in FIGS. 1 and 3 is a l2-circuitassembly. With two circuit breakers 61 connected to each of the sixstabs 45, a total of 12 circuit breakers can be mounted on the assemblyto feed and control 12 circuits drawn off of the two bus bars. Theinsulating support structure and bus bars for a 16- circuit assembly areillustrated in FIGS. 7 and 8. Since, except for differences that will behereinafter described, the parts of FIGS. 7 and 8 are like thosehereinbefore described with reference to FIGS. 3 and 1, primed referencecharacters are used in FIGS. 7 and 8 to identify the parts that are likethe parts of FIGS. 3 and 1. Different reference characters (69 and 70)are used to indicate that the insulating support structure 17 of FIG. 7comprises two insulating support members 69 and 70 rather than a singleinsulating support member as seen in FIG. 3. As can be seen in FIG. 7,each of the bus bars 39' and 41' comprises four stabs 45, and the twoinsulating support members 69, 70 cooperate to form the insulatingsupport structure 17' that is provided with eight stab-receiving slots27 for receiving the eight bus bar stabs 45.

During the mounting operation of the insulating support structure 17,the two insulating support members 69, 70 are moved into the positionseen in FIG. 8 with the slot portions 33 cooperating in the mannerdisclosed to provide an elongated insulating support structure 17'having the eight stab-receiving slots 27' therein. Screws 19 are passedthrough openings 35' in the insulating support structure 17' to securethe insulating support structure 17 to a mounting pan in the same mannerhereinbefore described. Thereafter, the

two bus bars 39', 41 are moved into the mounting position seen in FIG. 8in the same manner as was hereinbefore described with reference to FIGS.1-4. The panel assembly constructed with the parts of FIGS. 7 and 8 is al6-circuit assembly with eight stabs 45' being positioned in aninterleaved relationship aligned lengthwise along the insulating supportstructure 17 for receiving 16 circuit breakers that would be connectedto the assembly with each stab 45 feeding two circuit breakers in themanner described with the reference to FIGS. 1 and 2.

Single phase panel assemblies of the type herein described are generallyoffered in different circuit denominations. Manufactures may supplypanel assemblies comprising eight, l2, I6, 20, 24, 28, 32, 36, or

42 circuit breakers. In order to minimize the number of parts requiredper assembly, as sell as mold costs, the two different types ofinsulating support members disclosed in FIGS. 3 and 7 are constructedsuch that they can be used either along or in combination to constructany of the above-mentioned panel assemblies. As can beunderstood withreference to FIG. 7, each of the unitary molded insulating supportmembers 69 and 70 comprises four stab-receiving 'slots 27' for receivingfour bus bar stabs to supply eight circuits. In order to identify theseinsulating support members 69, 70 for the purpose of setting forth atable below, each of these insulating support members may be referred toas an A-block. As was previously described, the unitary moldedinsulating support member 17 of FIG. 3 com- No. of A Blocks No. of BBlocks No. of Circuits 8 l (l Another embodiment of the invention isdisclosed in FIG. 9. In FIG. 9, a supporting pan 7, similar to the onedisclosed in FIG. 1, is provided. Double primed reference characters areused in FIG. 9 in order to identify those parts that are like the partsdisclosed in FIG. I. An insulating support structure 17'', identical tothat disclosed in FIG. 1 is mounted on the'supporting pan 7". Two busbars 39" and 41" are supported on the insulating support structure 17"in the manner previously described with reference to FIGS. 1 and 3. Thebus bars 39" and 41" differ from the bus bars 39 and 41 only in that theupper ends of the bus bars terminate in the manner disclosed since thesebus bars need not extend upward to engage solderless terminal connectorsof the type disclosed in FIG. 1. Instead of energizing the bus bars 39"and 41" through solderless terminal connectors of the type disclosed at55 in FIG. I, a plug-in structure indicated generally at 81 is provided.The plug-in lug structure 81 comprises an insulating housing structure83 having two solderless terminal connectors 85 supported in cavities inthe housing 83. Two screws 87 connect two conducting straps 88 to thehousing 83. The conductors 88 connect the terminal conductors 85 withtwo well known types of clip-on terminals 89 that are mounted on theinsulating housing 83 and that clip onto the upper two stabs of the busbars 39", 41". The plug-in lug structure 81 is mounted on the panelassembly in the same manner as the circuit breakers. The plug-in lugstructure is first hooked under the two hooks 15" and then pivoted downinto the position seen in FIG. 9 with the two clip-on type terminalstructures clipping onto the upper two stabs of the bus bars 39", 41 Atthe installation, two conducting wires are brought into the panelassembly and connected to the solderless terminal connectors 85 in awell known manner to connect the two bus bars 39" and 41" to theconducting wires to thereby provide for energization of the bus bars. Inthe embodiment disclosed in FIG. 9, the insulating support structure 17supports the bus bars having a total of six stabs, and the upper twostabs are used for energizing the bus bars through the plug-in lugstructure. This leaves four stabs available to receive eight circuitbreakers in the same manner hereinbefore described. Thus, in thisembodimen't, the one B-block is used for an eight circuit assembly. Thefollowing table is set forth in order to illustrate the combination ofthe previously described A- and B-blocks that would be used for therequired circuit denominations when the plug-in lug structure 8lis usedto energize'the bus bars:

Quantity Quantity No. of Circuits of A Blocks of B Blocks 8 1 l2 2 0 l61 l 20 V 0 2 24 2 l 28 l 2 32 0 3 36 2' 2 40 l 3 42 O 4 While theinvention has been disclosed in accordance with the provisions of thepatent statutes, it is to be unl derstood that various changes in thestructural details and arrangement of parts thereof may be made withoutdeparting from some of the essential features of the invention. It isdesired, therefore, that the language of the appended claims be given asreasonably broad an interpretation as is permitted by the prior art.

What is claimed is: Y

1. YA panel assembly comprising an elongated insulating supportstructure and a pair of elongated bus bars, each bus bar comprising anelongated body portion and a plurality of stabs extending from the bodyportion in a longitudinally spaced relationship, the body portion havingopening'm'eans therein, the insulating support structure comprising aplurality of longitudinally spaced ledge parts at each of two oppositesides thereof, a plurality of transversely extending, longitudinallyspaced, pillar portions extending from each side of the body portion ofthe insulating support structure, at each of said two opposite sides ofsaid insulating support structure all adjacent spaced ledge parts beingspaced by a stab-receiving slot, said ledge parts and saidstab-receiving slots of said two opposite sides being staggeredlengthwise such that each stab-receiving slot at each side of saidinsulating support structure is opposite a ledge part of the oppositeside of said insulating support structure, said pair of bus bars beingsupported on said opposite sides of said insulating support struc: turewith the spaced stabs of each bus bar being positioned in the associatedslots and with the spaced ledge parts of the associated side beingpositioned over parts of the main body part of the associated bus bars,said stabs of said hair of bus bars being positioned in an interleavedrelationship aligned lengthwise along siad insulating support structure,said insulating support structure comprising support-surface means ateach of said two opposite sides thereof, each of said bus bars beingsupported over the associated support-surface means resting on theassociated support-surface means, and projection means on the top sideof said pillar portion cooperating with the opening means on said bodyportions of .said bus bars to retain said bus bars in the mountedposition on said insulating support structure.

2. The panel assembly according to claim 1, said insulating supportstructure comprising an integral molded unitary member.

3. The panel assembly according to claim 1, said insulating supportstructure comprising a plurality of molded insulating members supportedin an erld-to-end relationship.

4. The panel assembly according to claim 1, said projection means andsaid opening means comprising cooperating interengaging snap-in partsfor retaining said bus bars in the mounted position on said insulatingsupport structure.

5.-The panel assembly according to claim 1, said pillar portionscomprising support-surface means at each of said two opposite sidesthereof, each of said bus bars being supported on the associatedsupport-surface 5 means, said parts comprising projection means, the

opening means of each of said bus bars being at the main body partthereof, and said projection means being positioned in said openingmeans of said bus bars to retain said bus bars in the mounted positionon said insulating support structure.

6. The panel assembly according to claim 5, said insulating supportstructure and said bus bars being constructed such that as said bus barsmoved into the mounted position thereof said pillar positions are flexedin a direction away from said support-surface means and when said busbars reach the fully mounted position thereof said projection means willbe aligned with said opening means whereby said flexed pillar por tionmeans will uniflex moving said projection means into said opening meansto maintain said bus bars in the mounted position on said insulatingsupport structure.

7. The panel assembly according to claim 6, said pillar portion beingunder the associated stab-receiving slot to provide a support surfaceunder each of said stabs.

8. The panel assembly according to claim 6, said pillar portion beingunder each of said slots, said supportsurface means comprising the frontsurfaces of said pillar portions, the thickness of the main body portionof each bus bars being a dimension greater than the dimension betweenthe associated projection means and the associated support-surface meanswhereby as said bus bars are moved toward the mounted position betweenthe associated ledge parts and the associated support-surface means saidledge parts are flexed generally away from said support surface meansand when said bus bars reach the fully mounted position thereof saidprojections become aligned with said openings whereupon said flexedledge parts unflex moving said projection means into the associatedopening means to thereby maintain said bus bars in the mounted positionon said insulating support structure.

9. The panel assembly according to claim 8, said ledge parts havingsecond supportsurfaces on the side of the bus bars opposite that of saidsupport-surfaces of the pillar portions, and said second supportsurfaces having protrusion means engageable with the bus bars.

1. A panel assembly comprising an elongated insulating support structureand a pair of elongated bus bars, each bus bar comprising an elongatedbody portion and a plurality of stabs extending from the body portion ina longitudinally spaced relationship, the body portion having openingmeans therein, the insulating support structure comprising a pluralityof longitudinally spaced ledge parts at each of two opposite sidesthereof, a plurality of transversely extending, longitudinally spaced,pillar portions extending from each side of the body portion of theinsulating support structure, at each of said two opposite sides of saidinsulating support structure all adjacent spaced ledge parts beingspaced by a stab-receiving slot, said ledge parts and saidstab-receiving slots of said two opposite sides being staggeredlengthwise such that each stab-receiving slot at each side of saidinsulating support structure is opposite a ledge part of the oppositeside of said insulating support structure, said pair of bus bars beingsupported on said opposite sides of said insulating support structurewith the spaced stabs of each bus bar being positioned in the associatedslots and with the spaced ledge parts of the associated side beingpositioned over parts of the main body part of the associated bus bars,said stabs of said bair of bus bars being positioned in an interleavedrelationship aligned lengthwise along siad insulating support structure,said insulating suppOrt structure comprising support-surface means ateach of said two opposite sides thereof, each of said bus bars beingsupported over the associated support-surface means resting on theassociated support-surface means, and projection means on the top sideof said pillar portion cooperating with the opening means on said bodyportions of said bus bars to retain said bus bars in the mountedposition on said insulating support structure.
 2. The panel assemblyaccording to claim 1, said insulating support structure comprising anintegral molded unitary member.
 3. The panel assembly according to claim1, said insulating support structure comprising a plurality of moldedinsulating members supported in an end-to-end relationship.
 4. The panelassembly according to claim 1, said projection means and said openingmeans comprising cooperating interengaging snap-in parts for retainingsaid bus bars in the mounted position on said insulating supportstructure.
 5. The panel assembly according to claim 1, said pillarportions comprising support-surface means at each of said two oppositesides thereof, each of said bus bars being supported on the associatedsupport-surface means, said parts comprising projection means, theopening means of each of said bus bars being at the main body partthereof, and said projection means being positioned in said openingmeans of said bus bars to retain said bus bars in the mounted positionon said insulating support structure.
 6. The panel assembly according toclaim 5, said insulating support structure and said bus bars beingconstructed such that as said bus bars moved into the mounted positionthereof said pillar positions are flexed in a direction away from saidsupport-surface means and when said bus bars reach the fully mountedposition thereof said projection means will be aligned with said openingmeans whereby said flexed pillar portion means will uniflex moving saidprojection means into said opening means to maintain said bus bars inthe mounted position on said insulating support structure.
 7. The panelassembly according to claim 6, said pillar portion being under theassociated stab-receiving slot to provide a support surface under eachof said stabs.
 8. The panel assembly according to claim 6, said pillarportion being under each of said slots, said support-surface meanscomprising the front surfaces of said pillar portions, the thickness ofthe main body portion of each bus bars being a dimension greater thanthe dimension between the associated projection means and the associatedsupport-surface means whereby as said bus bars are moved toward themounted position between the associated ledge parts and the associatedsupport-surface means said ledge parts are flexed generally away fromsaid support surface means and when said bus bars reach the fullymounted position thereof said projections become aligned with saidopenings whereupon said flexed ledge parts unflex moving said projectionmeans into the associated opening means to thereby maintain said busbars in the mounted position on said insulating support structure. 9.The panel assembly according to claim 8, said ledge parts having secondsupport surfaces on the side of the bus bars opposite that of saidsupport-surfaces of the pillar portions, and said second supportsurfaces having protrusion means engageable with the bus bars.